Process for producing asphalt



Patented Oct. 24, 1944 2,361,263 I PROCESS FOR PRODUCING ASPHALT Donald E. Carr, .Los Angeles, Calif., assignor to Union Oil Company of California, Los Angeles, *Califi, a corporation of California No Drawing Application January 18, 1943,

Serial No. 472,743

I 8 Claims. This invention relates to manufacture of oxidized or air-blown asphalt from petroleum,

petroleum residuum and the like.

It is well known to produce oxidized asphalts by blowing petroleum oils, such as petroleum residua,

with air or other oxygen-containing gases at elevated temperatures for a sufiicient period of time until the desired change in melting point is obtained. Air-blowing the petroleum oil has the effect of raising the melting point, lowering the penetration and ductilityand also lowering the susceptibility of the asphalt to temperature changes, thus rendering the asphalt particularly suitable for roof coating, water-proofing and similar purposes requiring a, bituminous material of high melting point and low temperature susceptibility. However, this older method of producing oxidized asphalt is very tedious and requires considerable time, often taking as much as 20 to 40 hours of blowing time in order to produce the asphalt of desired melting point-penetration characteristics.

It is among the objects of my invention to provide a process for producing oxidized asphalt wherein it is possible to accelerate the oxidization reaction time over that customary in asphalt production and at the same time producing asphalts of superior characteristics.

I have found that air-blowing petroleum oil in the presence of a relatively small amount of certain types of compounds catalyzes the oxidation reaction to such extent that the air-blowing time, is considerably shortened. In accordance with my invention, a relatively small amount, 1. e. 0.1 to 2% by weight of a chlorinated hydrocarbon, is added to the petroleum stock to be subjected to air-blowing and the mixture is subjected to air-blowing in the usual manner, preferably at elevated temperatures of approximately 350-550 F., until an asphalt is produced having the desired melting point and penetration.

Air-blowing the petroleum stock in the presence of a small amount of the chlorinated hydrocarbon will not only shorten the time required to produce an asphalt of high melting point but will also produce an asphalt of a higher penetration and ductility for a given melting point than can be obtained by air-blowing, under similar conditions, the same petroleum stock without the addition of the chlorinated hydrocarbon.

Chlorinated hydrocarbons which may be employed in accordance with my invention include chlorinated petroleum oils, such as chlorinated kerosene, gas oil, lubricating oil and chlorinated high molecular weight hydrocarbons such as chlorinated wax. I have found chlorinated waxes to be particularly desirable for this purpose, Of these, I have found chlorinated waxes obtained by chlorinating waxes derived from petroleum and containing about 10-30% chlorine to be particularly suitable, although other waxes which have been chlorinated accelerate the oxidation reaction and produce asphalts of improved characteristics. and low melting Waxes such as scale wax, slack wax, match wax and foots oil which have been chlorinated by bubbling chlorine until about 10-30% chlorine has been adsorbed. It is preferable to restrict the degree of chlorination in order to produce a product which is composed essentially of chloroparaffins since a larger proportion of dichloroparafiins. and higher will be produced as the degree of chlorination is increased. The latter chlorinated hydrocarbons are not as eiiective as oxidation catalysts in asphalt making.

The invention may perhaps be better understood from the following example:

, A petroleum residuum obtained from a Santa Maria Valley asphaltic crude oil and having a viscosity of 693 seconds Saybolt Furol at 210 F. and a flash point of 425 F., Cleveland open cup, was placed in a vertical still provided with a spider at its lower extremity for the introduction of air or other oxygen-containing gas. The residuum was heated to 9, temperature of about 400 F. and then about 0.5% by weight, based on the residuum, of a chlorinated wax was mixed with the heated residuum. The blend was subjected to air-blowing at a temperature of about 480-490" F. for about 15.5 hours employing air at a rate of 2 cubic feet per minute per barrel of charge of residuum.

The chlorinated Wax employed in this example was produced from a crude petroleum scale wax of about 124 F. melting point which had been chlorinated by bubbling in chlorine while stirring and maintaining a temperature of about 150-180 F. until the wax had absorbed about 20% of its weight. of the chlorine.

The oxidized asphalt produced at the end of about 15.5 hours of air-blowing had a melting point of 207 F., penetrations of 9, 18 and 36 at 32, 77 and 115 F., respectively, a flash point of 485 F. (Cleveland open cup); a ductility of about 4.4 cm. at 77 F. and solubilities of 99.91, 99.87

and 62.8% in carbon bisulfide, carbon tetrachloride and 82 naphtha, respectively.

For comparison, another charge of the above Santa Maria Valley residuum was air-blown 11n- Such waxes include both high der similar conditions in the absence of the chlorinated wax to approximately the same melting point of about 207 F. This required about 22 hours and produced an asphalt having penetrations of 8, 14 and 30 at 32, '77 and 115 F., respectively, a flash point of 445 F. (Cleveland open cup), a ductility of about 3.5 cm. at 77 F. and solubilities of 99.71, 99.73 and '70 in carbon bisulfide, carbon tetrachloride and 82 naphtha, respectively.

The comparative run indicates that a superior melting point-penetration-ductility relationship characteristic is obtained by air-blowing the charge in the presence of the chlorinated wax. Also, the flash point Wax improved.

The foregoing description of my invention is not to be taken as limiting but merely as illustrative thereof since many variations may be made by those skilled in the art without departing from the scope of the following claims.

I claim:

1. A process for producing asphalt which comprises incorporating a relatively small amount of a chlorinated hydrocarbon in a petroleum oil fraction and commingling said oil with oxygencontaining gas at an elevated oxidizing temperature.

2. A process for producing asphalt which comprises incorporating a relatively small amount of a chlorinated hydrocarbon containing approximately 10-30% chlorine in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature.

3. A process for producing asphalt which comprises incorporating a relatively small amount of chloroparaflln in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature.

4. A process for producing asphalt which comprices incorporating a relatively small amount of a chlorinated petroleum oil in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature.

5. A process for producing asphalt which comprises incorporating a relatively small amount of a chlorinated high molecular weight hydrocarbon in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature.

6. A process for producing asphalt which comprises incorporating a relatively small amount of a chlorinated wax in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature.

7. A process for producing asphalt which comprises incorporating approximately 0.1 to 2% by weight of a chlorinated hydrocarbon in a petroleum oil fraction and commingling said oil with oxygen-containing gas at an elevated oxidizing temperature. 7

8. A process for producing asphalt which comprises incorporating a relatively small amount of a chlorinated hydrocarbon in a petroleum oil fraction and commingling said oil with oxygencontaining gas at a temperature of approximately 350-550 F.

DONALD E. CARR. 

